A hub unit for a vehicle exists, e.g., as disclosed in Patent Document 1. Generally, in a hub unit, a fixing member to be fixed to a vehicle body is mounted on an outer ring member, and a wheel is mounted on an inner ring member. As shown in FIG. 3, such a hub unit may be configured such that an outer ring member 2 includes an outer ring flange portion 22 formed to protrude from an outer circumferential surface thereof so as to contact a fixing member 9 of a vehicle body in an axial direction.